Heretofore, efforts have been made to provide useful devices for determining characteristics of textile yarns such as strength, regularity, weight, and twist or torque. It is important to be able to accurately determine and know these characteristics so that the quality and appearance of the final cloth or fabric can be controlled. In particular, yarns with too much torque or twist cause problems in final woven and knit fabrics and such excessive torque may, in the case of spun yarns, be reduced by steaming the yarn. When we have problems with spun yarns, we have a tendency to overreact. Therefore, the amount of steam used to overcome a torque problem could possibly be reduced if the yarn torque is predetermined to be within the acceptable torque range. The individual customer could specify the required torque level for the product produced.
A textured yarn torque problem may be dealt with by varying the twist level as well as the heater temperature. Depending on whether the product is a stretch or set yarn, the condition will vary.
If, for example, a standardized test and index for the torque were available to both the yarn supplier and the knitting plant then the exact torque index for the yarn could be specified by the knitter and the supplier could predetermine that the yarn so supplied meets the specified torque index. The index, most likely, will vary by type machine and/or creel for the knitting machine as well as the conditioning in the plant.
A device for measuring variations in the elongation of a running length of yarn is described in U.S. Pat. No. 3,018,659 wherein a strain gauge mechanism is used to obtain a stress-strain curve on a running strand of yarn subjected to a predetermined load.
A prior device developed for measuring torque in yarn is described in U.S. Pat. No. 2,154,631 wherein a length of yarn is supported at two ends, one end being free to rotate. The yarn is immersed in a liquid which releases the torque in the yarn rotating the free end an amount proportional to the torque which is registered on an indicating drum. Such a device comprises a rather large number of intricate components which detracts from the accuracy and uniformity of the measurements made therefrom.
Accordingly, the main object of this invention is to provide a device which will indicate the torque in a textured or spun yarn in a reliable and uniform manner affording a uniform means of measuring the torque in a given yarn in a reliable manner.
Another important object of the present invention is to provide a device for indicating the amount of torque in a textured or spun yarn which is simple in construction and operation.
Another important object of the present invention is to provide a torque indicating device for predetermining torque in textured and spun yarns so that problem yarns can be eliminated prior to further processing, eliminating the need and expense of faulty fabric.
Another important object of the present invention is to provide a torque indicating device which is readily available for all types of textile manufacturing operations.